Background: HIV transmission during pregnancy and breastfeeding among serodiscordant
heterosexual couples represents an ongoing barrier to the elimination of vertical transmission
of HIV-1 infection in Canada.
Objective: To report a case of vertical HIV transmission during breastfeeding and examine the prevalence
of risk factors for HIV transmission in the pregnancy and postpartum periods among
serodiscordant couples where the male partner is HIV positive and female partner HIV negative.
Methods: Case report and retrospective chart review of HIV-serodiscordant pregnant couples over
an eight-year period in Edmonton, Canada.
Results: We report a case of maternal primary HIV infection during the postpartum period and vertical
transmission to a nursing infant that went undetected until the infant presented with AIDS.
We also report a series of 41 serodiscordant pregnant couples identified by our public health nurse
between 2008 and 2016. Among HIV-infected male partners, 20 (49%) had a detectable viral load
(VL) during their partner’s pregnancy and during breastfeeding, with median peak VL 4,700
copies/mL (range 49-120,000) and 5,100 copies/mL (range 40-120,000) during pregnancy and
breastfeeding, respectively. None of the female partners seroconverted during pregnancy, but three
seroconverted at 1.8, 2.4, and 6.9 years after delivery. No vertical transmission occurred.
Conclusion: Despite concerted attempts to minimize HIV transmission during pregnancy and
breastfeeding in our well-resourced setting, residual transmission risk remains due to non-suppressed
viral load within many HIV-serodiscordant pregnant couples.